set a default value if the mysql selection query return empty rows

Question

i have a select query in my php file as next >>

$sql = 'SELECT * 
    FROM notes
    WHERE notes.code_apogee='.$CA.'';

that return some empty rows where i should set a default value << 'en attend'

i used IFNULL as below :

SELECT IFNULL( (SELECT *
    FROM notes
    WHERE notes.code_apogee='.$CA') ,'en attend');

but an error appear

 MySQL a répondu: Documentation
#1241 - Operand should contain 1 column(s)

any help ?? please

How do you define "empty rows"? A specific column, or all the columns in a specific row? Can you give an example with your dataset? — Qirel
– Qirel, Commented Jun 5, 2017 at 23:41
in notes table i have a group of columns where code_apogee is one of them and i use it as condition at this case, some of rows return a blank field so wanna to put in a default value ? — oby trace
– oby trace, Commented Jun 5, 2017 at 23:48
I think (not sure): the function IFNULL only takes one single column/value as param. You give it several (as many as all the columns in table notes) — Jeff
– Jeff, Commented Jun 5, 2017 at 23:50

Jeff · Accepted Answer · 2017-06-06 00:01:17Z

3

IFNULL() won't take a subselect (which is all the columns in your case) as param, but just one (plus the else value).
So your query should be something like this:

SELECT id, 
    IFNULL(notes.title, 'en attend') as title, 
    IFNULL(notes.body, 'en attend') as body 
FROM notes
WHERE notes.code_apogee='.$CA'

(I just invented notes.title & notes.body, you need to replace that with actual column names)

You could of course let the db just return the NULLs and add 'en attend' when displaying the results:

echo !is_null($row['title']) ? $row['title'] : 'en attend';

edited Jun 6, 2017 at 0:01

answered Jun 5, 2017 at 23:54

Jeff

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